Method and system for a distributed receiver

ABSTRACT

A first semiconductor die may comprise an interface circuit and a demodulation circuit. The interface circuit may be operable to receive an externally generated signal and recover decisions of a symbol de-mapper carried in the externally generated signal. The demodulation circuit may be operable to recover one or more transport streams based on the decisions of the symbol de-mapper. The first semiconductor die may comprise circuitry operable to combine a plurality of signals from a plurality of second semiconductor dice, where each of the plurality of signals comprises decisions of a respective one of a plurality of symbol de-mappers.

PRIORITY CLAIM

This patent application makes reference to, claims priority to andclaims benefit from: U.S. Provisional Patent Application Ser. No.61/595,654 filed on Feb. 6, 2012; U.S. Provisional Patent ApplicationSer. No. 61/667,460 filed on Jul. 3, 2012; and U.S. Provisional PatentApplication Ser. No. 61/702,799 filed on Sep. 19, 2012.

Each of the above-identified applications is hereby incorporated hereinby reference in its entirety.

FIELD OF THE INVENTION

Certain embodiments of the invention relate to wireless communications.More specifically, certain embodiments of the invention relate to amethod and system for a distributed receiver.

BACKGROUND OF THE INVENTION

Conventional receivers are limited in terms of the performance they canhope to achieve due, for example, to size, location, and powerconsumption limitations. Further limitations and disadvantages ofconventional and traditional approaches will become apparent to one ofskill in the art, through comparison of such systems with some aspectsof the present invention as set forth in the remainder of the presentapplication with reference to the drawings.

BRIEF SUMMARY OF THE INVENTION

A system and/or method is provided for a distributed receiver,substantially as shown in and/or described in connection with at leastone of the figures, as set forth more completely in the claims.

These and other advantages, aspects and novel features of the presentinvention, as well as details of an illustrated embodiment thereof, willbe more fully understood from the following description and drawings.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

FIG. 1A depicts a first example receiver architecture in whichsubsystems are partitioned in a first manner.

FIG. 1B depicts a second example receiver architecture in whichsubsystems are partitioned in a second manner.

FIG. 1C depicts a third example receiver architecture in whichsubsystems are partitioned in a third manner.

FIG. 1D depicts a first example full-spectrum capture receiverarchitecture in which subsystems are partitioned in a first manner.

FIG. 1E depicts a second example full-spectrum capture receiverarchitecture in which subsystems are partitioned in a second manner.

FIG. 1F depicts a third example receiver full-spectrum capturearchitecture in which subsystems are partitioned in a third manner.

FIG. 2A depicts an example second subsystems operable to receive signalsfrom multiple instances of a first subsystem.

FIG. 2B depicts an example second subsystems operable to receive signalsfrom multiple instances of a first full-spectrum capture subsystem.

FIGS. 3A-3F depict example implementations of a distributed receiver.

FIG. 4 depicts an example fiber node using a distributed receiverarchitecture.

FIG. 5 is a flowchart illustrating an example process for reception viaa distributed receiver.

FIG. 6 depicts a portion of a distributed receiver.

FIG. 7 is a flowchart illustrating an example process for reception viaa distributed receiver.

DETAILED DESCRIPTION OF THE INVENTION

As utilized herein the terms “circuits” and “circuitry” refer tophysical electronic components (i.e. hardware) and any software and/orfirmware (“code”) which may configure the hardware, be executed by thehardware, and or otherwise be associated with the hardware. As usedherein, for example, a particular processor and memory may comprise afirst “circuit” when executing a first one or more lines of code and maycomprise a second “circuit” when executing a second one or more lines ofcode. As utilized herein, “and/or” means any one or more of the items inthe list joined by “and/or”. As an example, “x and/or y” means anyelement of the three-element set {(x), (y), (x, y)}. As another example,“x, y, and/or z” means any element of the seven-element set {(x), (y),(z), (x, y), (x, z), (y, z), (x, y, z)}. As utilized herein, the term“exemplary” means serving as a non-limiting example, instance, orillustration. As utilized herein, the terms “e.g.,” and “for example”set off lists of one or more non-limiting examples, instances, orillustrations. As utilized herein, circuitry is “operable” to perform afunction whenever the circuitry comprises the necessary hardware andcode (if any is necessary) to perform the function, regardless ofwhether performance of the function is disabled, or not enabled, by someuser-configurable setting.

FIG. 1A depicts a first example receiver architecture in whichsubsystems are partitioned in a first manner. The receiver in FIG. 1Acomprises a first subsystem 108 a and a second subsystem 110 a. In anexample implementation, the subsystem 108 a may be a first integratedcircuit fabricated using a first semiconductor process, and thesubsystem 110 a may be a second integrated circuit fabricated using asecond semiconductor process. For example, subsystem 108 a may befabricated using an X-nanometer silicon process, and subsystem 110 a maybe fabricated using a Y-nanometer silicon process, where X and Y arenumbers and X is greater than Y.

The example subsystem 108 a comprises a low-noise amplifier 102 operableto amplify a received RF signal.

The example subsystem 108 a comprises a quadrature mixer 104 operable togenerate an in-phase signal and a quadrature phase signal from thereceived RF signal. Additionally, the mixer 104 may be operable todownconvert the received RF signal. In other example implementations,the mixer 104 may not be a quadrature mixer. In such an implementation,a single signal, rather than I and Q signals, may be output to a singleADC, rather than a pair of ADCs. In other example implementations, thesubsystem 108 d may comprise an ADC that directly digitizes thereceived, filtered RF signal.

The example subsystem 108 a comprises a pair of filters 109 a and 109 boperable to filter, respectively, the in-phase and quadrature phaseoutputs of the mixer 104. Each of the filters 109 may comprise apassband corresponding to a desired frequency band and may providesufficient attenuation of signals outside the desired band.

The example subsystem 108 a comprises a pair of analog-to-digitalconverters 111 a and 111 b operable to digitize, respectively, thein-phase and quadrature phase outputs of the filters 111 a and 111 b.

The example subsystem 108 a comprises a digital front end (DFE) 112operable to combine the in-phase and quadrature-phase digitizedspectrums from the ADCs 111 a and 111 b (including performing filtering,noise cancellation, and/or other operations for improving signalquality).

The example subsystem 108 a comprises a demodulator 114. Each of thedemodulators may be operable to demodulate a signal in accordance withone or more standards/protocols to recover datastream (e.g., one or moreMPEG transport streams) contained in the signal. For example, each ofthe demodulators may be operable to perform demodulation operations(e.g., timing recovery, equalization, symbol slicing, deinterleaving,FEC decoding, and/or other operations) for signals generated inaccordance with one or more standards/protocols. Exampleprotocols/standards include terrestrial television standards/protocols,cable television standards/protocols, and DOCSIS standards/protocols,and Direct Broadcast Satellite (DBS) standards/protocols. Eachdemodulator 114 _(n) may output a respective one of N datastreamsrecovered from the received spectrum.

The example subsystem 108 a comprises an interface transmitter 116operable to transmit (and process as desired or necessary for thetransmission) the signal 115 onto the link 117. The link 117 may be awireline (e.g., cable or PCB trace), wireless, or fiber optic link. Invarious example implementations in which signals from multiplesubsystems 108 may be communicated to a single subsystem 110, theinterface transmitter 116 may perform time-stamping messages sent ontothe link 117. The subsystem 110 a may use the time-stamps for combiningthe received data (e.g., to determine which data from a first subsystem108 corresponds to which data from a second subsystem 108, and so on).

The example subsystem 110 a comprises an interface receiver 122 operableto receive the signal(s) over the link 117. In an exampleimplementation, the interface receiver 122 may be operable to performcombining (e.g., maximal ratio combining) and/or MIMO processing as, forexample, described below with reference to FIG. 2A.

The example subsystem 110 a comprises a media access control (MAC)and/or datastream processing circuit 124 operable to perform OSI layer 2(media access control) and, optionally, higher OSI layer (e.g., networklayer) processing of the datastream 115 (e.g., an MPEG transport stream115).

An advantage of the receiver architecture in FIG. 1A, relative to thearchitecture of FIG. 1B, is that the link 117 between the subsystems mayoperate at a lower data rate than the link 153 (e.g., because redundancyand other physical layer overhead has already been removed by thedemodulator 114). A disadvantage of the architecture in FIG. 1A,relative to the architecture of FIG. 1B, is that, where the subsystem108 a is implemented in a low-density (e.g., higher feature size)process (e.g., to improve analog performance), the demodulator(s) 114₁-114 _(N) may require a large amount die area (e.g. to accommodateinterleaver memory).

FIG. 1B depicts a second example receiver architecture in whichsubsystems are partitioned in a second manner. The receiver in FIG. 1Bcomprises a first subsystem 108 b and a second subsystem 110 b.

Like the example subsystem 108 a in FIG. 1A, the example subsystem 108 bcomprises the LNA 102, the VGAs 106, the filters 109, the ADCs 111, theDFE 112, and may or may not comprise one or more mixers 104. The examplesubsystem 108 b differs from the example subsystem 108 a in that it doesnot comprise a demodulator and that it comprises a different (ordifferently configured) interface transmitter 152. The interfacetransmitter 152 is operable to transmit (and process as necessary ordesired for transmission) the signal 113 onto the link 153. The link 153may be a wireline, wireless, or fiber optic link. In various exampleimplementations in which signals from multiple subsystems 108 may becommunicated to a single subsystem 110, the interface transmitter 116may perform time-stamping messages sent onto the link 117. The subsystem110 a may use the time-stamps for combining the received data (e.g., todetermine which data from a first subsystem 108 corresponds to whichdata from a second subsystem 108, and so on).

Like the example subsystem 110 a, the example subsystem 110 b comprisesthe MAC and/or datastream processing circuit 124. The example subsystem110 b differs from the example subsystem 110 a in that it comprises thedemodulator 144 and a different (or differently-configured) interfacereceiver 142. The interface receiver 142 may be operable to receive thesignal(s) over the link 153 to recover the channel 113. The demodulator144 may each be operable to perform the same functions as thedemodulator 114 described above with reference to FIG. 1A.

An advantage of the architecture of FIG. 1B relative to the architecturein FIG. 1A is that the demodulators may be integrated with digital-onlycircuitry, which may accommodate use of a higher-density process (e.g.,to reduce size of interleaver memory). A disadvantage of thearchitecture of FIG. 1B relative to the architecture of FIG. 1A is thatthe link 153 between the two subsystems may need to operate at a higherdata rate (e.g. 180 Mbps vs. 40 Mbps) than link 117.

FIG. 1C depicts a third example receiver architecture in whichsubsystems are partitioned in a third manner. Like the example subsystem108 a in FIG. 1A, the example subsystem 108 b comprises the LNA 102, theVGAs 106, the filters 109, the ADCs 111, the DFE 112, and may or may notcomprise one or more mixers 104. The example subsystem 108 c differsfrom the example subsystem 108 a in that it includes a partialdemodulator 162 and that it comprises a different (or differentlyconfigured) interface transmitter 164.

The partial demodulator 162 may be operable to perform a subset of thedemodulation operations (e.g., timing recovery, equalization, symbolslicing, etc.) for signals generated in accordance with one or morestandards/protocols. Example protocols/standards include terrestrialtelevision standards/protocols, cable television standards/protocols,and DOCSIS standards/protocols, and Direct Broadcast Satellite (DBS)standards/protocols. The partial demodulator 162 may output a signal 163which may, for example, be hard decision outputs of a symbol de-mapper,soft decision outputs of a symbol de-mapper (e.g., log-likelihoodratios), and/or equalizer settings (e.g., number of taps and/or tapcoefficients).

The interface transmitter 164 may be operable to transmit (and processesas necessary or desired for transmission) the signal 163 onto the link165. The link 164 may be a wireline, wireless, or fiber optic link.

Like the example subsystem 110 a, the example subsystem 110 c comprisesthe MAC and/or datastream processing circuit 124. The example subsystem110 c differs from the example subsystem 110 a in that it comprisespartial demodulator 168 and a different (or differently-configured)interface receiver 166. The interface receiver 166 may be operable toreceive the signal(s) over the link 165 to recover the signal 163. Thepartial demodulator 168 may be operable to perform a subset of thedemodulation operations (e.g., FEC decoding) that complement thedemodulation operations performed by the partial demodulator 162 (e.g.,that complete demodulation of signals generated in accordance with theapplicable standards/protocols).

The data rate of the link 165 may be somewhere between the data rate ofthe link 117 in FIG. 1A and the data rate of the link 153 of FIG. 1B.For example, the link 165 may operate at 54 Mbps, the link 153 mayoperate at 40 Mbps, and the link 117 may operate at 180 Mbps

An advantage of the architecture of FIG. 1C relative to the architecturein FIG. 1A is that most or all of the analog portions of thedemodulation operations may be performed in the subsystem 108 c that isimplemented in the lower-density process and most or all of the digitalportions of the demodulation process may be performed in the subsystem110 c that is implemented in higher-density process. Such a partitioningmay optimize the cost and size of the overall system comprisingsubsystems 108 c and 110 c.

FIG. 1D depicts a first example full-spectrum capture receiverarchitecture in which subsystems are partitioned in a first manner. Thereceiver in FIG. 1D comprises a first subsystem 108 d and a secondsubsystem 110 d. In an example implementation, the subsystem 108 d maybe a first integrated circuit fabricated using a first semiconductorprocess, and the subsystem 110 d may be a second integrated circuitfabricated using a second semiconductor process. For example, subsystem108 d may be fabricated using an X-nanometer silicon process, andsubsystem 110 d may be fabricated using a Y-nanometer silicon process,where X and Y are numbers and X is greater than Y.

The example subsystem 108 d comprises a low-noise amplifier 154 operableto amplify a received RF signal. The LNA 154 may be, for example, awideband amplifier operable to amplify the entire spectrum of acommunications protocol/standard of interest. For example, the LNA 154may be operable to amplify the entire cable television/DOCSIS spectrum(˜1 GHZ) and/or may be operable to amplify the entire spectrum (˜1 GHZ)of a direct broadcast satellite signal output by a low-noise blockdownconverter.

The example subsystem 108 d comprises a mixer 155 operable to generatean in-phase signal and a quadrature phase signal from the received RFsignal. Additionally, the mixer 155 may be operable to downconvert thereceived RF signal. Like the LNA 154, the mixer 155 may be sufficientlywideband to process the entire spectrum of the applicable communicationsprotocol/standard. In other example implementations, the mixer 104 maynot be a quadrature mixer. In such an implementation, a single signal,rather than I and Q signals, may be output to a single ADC, rather thana pair of ADCs. In other example implementations, the subsystem 108 dmay comprise an ADC that directly digitizes the received, filtered RFsignal.

The example subsystem 108 d comprises a pair of filters 158 a and 158 boperable to filter, respectively, the in-phase and quadrature phaseoutputs of the mixer 155. Each of the filters 158 may comprise apassband corresponding to the spectrum (the RF spectrum where the mixerdoes not perform downconversion and the IF or baseband spectrum wherethe mixer 155 does perform downconversion) of the communicationsprotocol/standard of interest, and may provide sufficient attenuation ofsignals outside the desired spectrum.

The example subsystem 108 d comprises a pair of analog-to-digitalconverters 159 a and 159 b operable to digitize, respectively, thein-phase and quadrature phase outputs of the filters 159 a and 159 b.Each of the ADCs 159 may be operable to concurrently digitize the entirespectrum of the applicable communications protocols/standard (e.g.,cable television/DOCSIS or direct broadcast satellite). In an exampleimplementation, each of the ADCs may be as described in U.S. patentapplication Ser. No. 13/485,003 and/or U.S. patent application Ser. No.13/336,451, each of which is hereby incorporated by reference in itsentirety.

The example subsystem 108 d comprises a digital front end (DFE) 160operable to combine the in-phase and quadrature-phase digitizedspectrums from the ADCs 159 a and 159 b (including performing filtering,noise cancellation, and/or other operations for improving signalquality), and to perform channelization of the resulting spectrum. Thechannelization may comprise selecting up to N (an integer) channels ofthe digitized spectrum for output as signals 113 ₁-113 _(N). Forexample, each of the channels 113 ₁-113 _(N) may comprise a 6 or 8 MHzwide television channel.

The example subsystem 108 d comprises a plurality, N, of thedemodulators 114. Each of the demodulators 114 may be as described withreference to FIG. 1A.

The example subsystem 108 d comprises an interface transmitter 176operable to multiplex the datastreams 115 ₁-115 _(N) (e.g., MPEGtransport streams) onto a link 177 (which may comprise, for example,fewer than N conductors). The link 177 connects subsystem 108 d tosubsystem 110 d. The link 177 may be a wireline, wireless, or fiberoptic link. In various example implementations in which signals frommultiple subsystems 108 may be communicated to a single subsystem 110,the interface transmitter 176 may perform time-stamping messages sentonto the link 177. The subsystem 110 d may use the time-stamps forcombining the received data (e.g., to determine which data from a firstsubsystem 108 corresponds to which data from a second subsystem 108, andso on).

The example subsystem 110 d comprises an interface receiver 178 operableto receive the signal(s) over the link 177 and de-multiplex thesignal(s) to recover the datastreams 115 ₁-115 _(N). In an exampleimplementation, the interface receiver 178 may be operable to performcombining (e.g., maximal ratio combining) and/or MIMO processing as, forexample, described below with reference to FIG. 2B.

The example subsystem 110 d comprises a media access control (MAC)and/or datastream processing circuit 124 operable to perform OSI layer 2(media access control) and, optionally, higher OSI layer (e.g., networklayer) processing of the datastreams 115 ₁-115 _(N) (e.g., MPEGtransport streams).

An advantage of the receiver architecture in FIG. 1D, relative to thearchitecture of FIG. 1E, is that the link 177 between the subsystems mayoperate at a lower data rate than the link 183 (e.g., because redundancyand other physical layer overhead has already been removed by thedemodulators 114). A disadvantage of the architecture in FIG. 1D,relative to the architecture of FIG. 1E, is that, where the subsystem108 d is implemented in a low-density (e.g., higher feature size)process (e.g., to improve analog performance), the demodulator(s) 114₁-114 _(N) may require a large amount die area (e.g. to accommodateinterleaver memory).

FIG. 1E depicts a second example full-spectrum capture receiverarchitecture in which subsystems are partitioned in a second manner. Thereceiver in FIG. 1E comprises a first subsystem 108 e and a secondsubsystem 110 e.

Like the example subsystem 108 d in FIG. 1D, the example subsystem 108 ecomprises the LNA 154, the VGAs 156, the filters 158, the ADCs 159, theDFE 160, and may or may not comprise one or more mixers 155. The examplesubsystem 108 e differs from the example subsystem 108 d in that it doesnot comprise demodulators and that it comprises a different (ordifferently configured) interface transmitter 182. The interfacetransmitter 182 multiplexes the channels 113 ₁-113 _(N) onto the link183 (which may comprise, for example, fewer than N conductors). The link183 connects subsystem 108 e to subsystem 110 e. The link 183 may be awireline, wireless, or fiber optic link. In various exampleimplementations in which signals from multiple subsystems 108 may becommunicated to a single subsystem 110, the interface transmitter 182may perform time-stamping messages sent onto the link 183. The subsystem110 e may use the time-stamps for combining the received data (e.g., todetermine which data from a first subsystem 108 corresponds to whichdata from a second subsystem 108, and so on).

Like the example subsystem 110 d, the example subsystem 110 e comprisesthe MAC and/or datastream processing circuit 124. The example subsystem110 e differs from the example subsystem 110 d in that it comprisesdemodulators 144 ₁-144 _(N) and a different (or differently-configured)interface receiver 184. The interface receiver 184 may be operable toreceive the signal(s) over the link 183 and de-multiplex the signal(s)to recover the channels 113 ₁-113 _(N). The demodulators 144 ₁-144 _(N)may each be operable to perform the same functions as the demodulators114 ₁-114 _(N) described above with reference to FIG. 1D.

An advantage of the architecture of FIG. 1E relative to the architecturein FIG. 1D is that the demodulators may be integrated with digital-onlycircuitry, which may accommodate use of a higher-density process (e.g.,to reduce size of interleaver memory). A disadvantage of thearchitecture of FIG. 1E relative to the architecture of FIG. 1D is thatthe link 183 between the two subsystems may need to operate at a higherdata rate (e.g. 180 Mbps vs. 40 Mbps).

FIG. 1F depicts a third example receiver architecture in whichsubsystems are partitioned in a third manner. Like the example subsystem108 d in FIG. 1D, the example subsystem 108 f comprises the LNA 154, theVGAs 156, the filters 158, the ADCs 159, the DFE 160, and may or may notcomprise one or more mixers 155. The example subsystem 108 f differsfrom the example subsystem 108 d in that it includes partialdemodulators 162 ₁-162 _(N) and that it comprises a different (ordifferently configured) interface transmitter 194.

Each of the partial demodulators 162 ₁-162 _(N) may be operable toperform a subset of the demodulation operations (e.g., timing recovery,equalization, symbol slicing, etc.) for signals generated in accordancewith one or more standards/protocols. Example protocols/standardsinclude terrestrial television standards/protocols, cable televisionstandards/protocols, and DOCSIS standards/protocols, and DirectBroadcast Satellite (DBS) standards/protocols. Each partial demodulator162 ₁-162 _(N) may output a respective one of signals 163 ₁-163 _(N)which may, for example, be hard decision outputs of a symbol de-mapper,soft decision outputs of a symbol de-mapper (e.g., log-likelihoodratios), and/or equalizer settings (e.g., number of taps and/or tapcoefficients).

The interface transmitter 164 may be operable to multiplex the signals163 ₁-163 _(N) onto the link 195 (which may comprise, for example, fewerthan N conductors). The link 195 connects subsystem 108 c to subsystem110 c. The link 195 may be a wireline, wireless, or fiber optic link. Invarious example implementations in which signals from multiplesubsystems 108 may be communicated to a single subsystem 110, theinterface transmitter 194 may perform time-stamping messages sent ontothe link 195. The subsystem 110 f may use the time-stamps for combiningthe received data (e.g., to determine which data from a first subsystem108 corresponds to which data from a second subsystem 108, and so on).

Like the example subsystem 110 d, the example subsystem 110 f comprisesthe datastream processing circuit 124. The example subsystem 110 fdiffers from the example subsystem 110 d in that it comprises partialdemodulators 168 ₁-168 _(N) and a different (or differently configured)interface receiver 196. The interface receiver 196 may be operable toreceive the signal(s) over the link 194 and de-multiplex the signal(s)to recover the signals 163 ₁-163 _(N). The partial demodulators 168₁-168 _(N) may each be operable to perform a subset of the demodulationoperations (e.g., FEC decoding) that complement demodulation operationsperformed by the partial demodulators 162 ₁-162 _(N) (e.g., thatcomplete demodulation of signals generated in accordance with theapplicable standards/protocols).

The data rate of the link 195 may be somewhere between the data rate ofthe link 177 in FIG. 1D and the data rate of the link 183 of FIG. 1E.For example, the link 195 may operate at 54 Mbps, the link 195 mayoperate at 40 Mbps, and the link 177 may operate at 180 Mbps

An advantage of the architecture of FIG. 1F relative to the architecturein FIG. 1D is that most or all of the analog portions of thedemodulation operations may be performed in the subsystem 108 f that isimplemented in the lower-density process and most or all of the digitalportions of the demodulation process may be performed in the subsystem110 f that is implemented in higher-density process. Such a partitioningmay optimize the cost and size of the overall system comprisingsubsystems 108 f and 110 f.

In the remainder of this disclosure, references to subsystem 108 mayrefer to any of the subsystems 108 a, 108 b, 108 c, 108 d, 108 e, and108 f or variations thereof, and references to subsystem 110 may referto any of the subsystems 110 a, 110 b, 110 c, 110 d, 110 e, and 110 f orvariations thereof—with the assumption that the subsystems are properlypaired (i.e., 108 a is used with 110 a, 108 b is used with 110 b, 108 cis used with 110 c, 108 d is used with 110 d, 108 e is used with 110 e,108 f is used with 110 f).

FIG. 2A depicts an example second subsystems operable to receive signalsfrom multiple instances of a first subsystem. Each of the signals 201₁-201 _(M) corresponds to a signal received over any of the links 117,153, and 165. The interface receiver 202 corresponds to any of theinterface receivers 122, 142, and 166. The demodulator 204 correspondsto either of the demodulator 144 and the partial demodulator 168. Ininstances that each of the signals 201 ₁-201 _(M) corresponds to thesame received signal, the interface receiver 202 may coherently combinethe signals 201 ₁-201 _(M) (e.g., using maximal ratio combining) torecover the signal. In instances that each of the signals 201 ₁-201 _(M)corresponds to a different received signal, the interface receiver 202may combine the signals 201 ₁-201 _(M) (e.g., in accordance with amultiple-in-multiple-out (MIMO) scheme) to recover the signals.

FIG. 2B depicts an example second subsystems operable to receive signalsfrom multiple instances of a first full-spectrum capture subsystem. Eachof the signals 221 ₁-221 _(M) corresponds to a signal received over anyof the links 177, 183, and 195. The interface receiver 222 correspondsto any of the interface receivers 178, 184, and 196. Each of thedemodulators 224 ₁-224 _(N) corresponds to either of the demodulator 144and the partial demodulator 168. In instances that each of the signals221 ₁-221 _(M) corresponds to the same received signal, the interfacereceiver 222 may coherently combine the signals 221 ₁-221 _(M) (e.g.,using maximal ratio combining) to recover the signal. In instances thateach of the signals 221 ₁-221 _(M) corresponds to a different receivedsignal, the interface receiver 222 may combine the signals 221 ₁-221_(M) (e.g., in accordance with a multiple-in-multiple-out (MIMO) scheme)to recover the signals.

FIGS. 3A-3F depict example implementations of a distributed receiver. Inthe example implementations depicted, the signals from multiplesubsystems 108 are combined in the subsystem 210 as described above withreference to FIGS. 2A and/or 2B.

In FIGS. 3A and 3B, a plurality of instances of the subsystem 108 aredistributed throughout a premises. Each of the subsystems 108 ₁-108 ₄receives a wireless signal (e.g., a terrestrial television signal or acellular signal). Each of the subsystems 108 ₁-108 ₄ processes thereceived signal as described above with reference to FIGS. 1A, 1B, 1C,1D, 1E, and/or 1F and output a signal such as is output via link 117,153, 165, 177, 183, and/or 195. For example, in FIG. 3A the interfacetransmitters of the subsystems 108 may transmit in accordance with awireless protocol such as Wi-Fi, Zigbee, wireless USB, or the like, andin FIG. 3B the interface transmitters of the subsystems 108 may transmitin accordance with a wireline protocol such as 10/100/1GBASE-T, Ethernetover Coax, USB, IEEE-1394, or the like, or a fiber optic protocol suchEthernet over Passive Optical Network (EPON).

In FIGS. 3C and 3D, an instance of the subsystem 108 resides in each ofa plurality of satellite reception assemblies 312 (e.g., DBS satellite“dishes”). Each of the subsystems 108 receives a down-convertedsatellite signal from a respective one of low noise blockdown-converters (LNBs) 304 ₁ and 304 ₂. Each subsystem 108 processes itsrespective satellite signal as described above with reference to FIGS.1A, 1B, 1C, 1D, 1E, and/or 1F, and outputs a signal such as is sent overthe link 117, 153, 165, 177, 183, and/or 195.

In FIG. 3C, the outputs of the subsystems 108 ₁-108 ₂ are conveyed, vialinks 308 (e.g., coaxial cables), to an indoor unit 302 (e.g.,comprising a satellite set-top box and DSL modem, or a terrestrialtelevision receiver) comprising an instance of subsystem 210. In FIG.3D, the outputs of the subsystems 108 ₁-108 ₂ may be conveyed (e.g.,using Ethernet, MoCA, HDMI, or the like), via links 310 (e.g., coaxialcables), to a hub 314 and one or more gateways 302 (which together maybe referred to as an “indoor unit”). FIG. 3E depicts the hub 314 in amulti-dwelling unit (MDU) serving a plurality of gateways 302.

In an example implementation, each of three satellite dish assemblies312 ₁, 312 ₂, and 312 ₃ may be substantially the same and may allcollect the same satellite signal—with each collected signal havingdifferent noise levels and noise characteristics due, for example, toslightly different location, alignment, non-idealities in theelectronics, etc. A subsystem 108 of each of the satellite dishassemblies may output a signal to a subsystem 210. The power from thecollected signals may be combined by the interface receiver of thesubsystem 210. In such an implementation, the combined signal power (inlog units) may increases by 20 log(3) while the noise power combinesnon-coherently and increases by 10 log(3). This would lead to a netimprovement in signal-to-noise ratio (SNR) of 10 log(3) in the logdomain, or 3 in the linear domain. In other words, the effective gain ofthe combined antenna may be increased a factor of 3 compared with thegain of one satellite reception assembly. In one such exampleimplementation, digitized signal information may be output from each ofthe subassemblies 108 ₁-108 ₃ of the three satellite receptionassemblies and combined in the in the subsystem 210 which may use, forexample, maximum ratio combining. The resulting diversity combinedsignal may then be demodulated in the subsystem 210. The cascading ofsatellite reception assemblies 312 in close proximity to one another maybe done, for example, in an area which has poor satellite reception. Insuch an area, multiple satellite reception assemblies may be placed, forexample, next to each other on the roof of a house and/or the roofs ofneighboring houses and used to collect the signals, which may then becombined to achieve better reception.

FIG. 3F depicts an example implementation in which a plurality of remoteradio units (RRUs) of a cellular basestation comprise a plurality ofsubsystems 108 and the subsystems 108 output signals to a baseband unit(BBU) of the basestation.

FIG. 4 depicts an example cable modem termination system (CMTS) andfiber node using a distributed receiver architecture. Shown in FIG. 4,is a CMTS 402, a fiber node 404, and customer premise equipment (CPE)406, each comprising one or more instances of subsystem 108 andsubsystem 110.

Fiber downstream traffic may be conveyed from the subsystem 108 _(FDS)in the CMTS 402 to the subsystem 110 _(FDS) in the fiber node 404.Accordingly, the interface transmitter and receiver of the subsystems108 _(FDS) and 110 _(FDS) may be operable to communicate over the fiberoptic cable 404. For example, the subsystem 108 _(FDS) may correspond tothe subsystem 108 c in FIG. 1C, the subsystem 110 _(FDS) may correspondto the subsystem 110 c, and soft-decision outputs (e.g., LLRs) of ade-mapper may be sent over the fiber 404.

Fiber upstream traffic may be conveyed from the subsystem 108 _(FUS) inthe fiber node 404 to the subsystem 110 _(FUS) in the CMTS 402.Accordingly, the interface transmitter and receiver of the subsystems108 _(FUS) and 110 _(FUS) may be operable to communicate over the fiberoptic cable 404. For example, the subsystem 108 _(FUS) may correspond tothe subsystem 108 c in FIG. 1C, the subsystem 110 _(FUS) may correspondto the subsystem 110 c, and soft-decision outputs (e.g., LLRs) of ade-mapper may be sent over the fiber 404.

Coaxial downstream traffic may be conveyed from the subsystem 108 _(CDS)in the fiber node 404 to the subsystem 110 _(CDS) in the CPE 406.Accordingly, the interface transmitter and receiver of the subsystems108 _(CDS) and 110 _(CDS) may be operable to communicate over thecoaxial cable 404. For example, the subsystem 108 _(CDS) may correspondto the subsystem 108 c in FIG. 1C, the subsystem 110 _(CDS) maycorrespond to the subsystem 110 c, and soft-decision outputs (e.g.,LLRs) of a de-mapper may be sent over the coaxial cable 405.

Coaxial upstream traffic may be conveyed from the subsystem 108 _(CUS)in the CPE 406 to the subsystem 110 _(CUS) in the fiber node 404.Accordingly, the interface transmitter and receiver of the subsystems108 _(CUS) and 110 _(CUS) may be operable to communicate over thecoaxial cable 405. For example, the subsystem 108 _(CUS) may correspondto the subsystem 108 c in FIG. 1C, the subsystem 110 _(CUS) maycorrespond to the subsystem 110 c, and soft-decision outputs (e.g.,LLRs) of a de-mapper may be sent over the coaxial cable 405.

FIG. 5 is a flowchart illustrating an example process for reception viaa distributed receiver. The process begins with block 502 in which awireless signal is received by a plurality of subsystems 108. The signalmay be of any frequency and/or standard. In block 504 each of thesubsystems 108 digitizes and equalizes the received signal. For example,for a satellite broadcast television signal, an entire ˜1 GHz spectrumfrom a LNB may be digitized and equalized. In block 506, the subsystem108 may slice the digitized symbols. The slicing may comprise generatinghard and/or soft decisions (e.g., LLRs) regarding what symbol wasreceived at particular time instants. In block 510, the hard and/or softdecisions and/or EQ settings (where the subsystem 108 is in a fixedlocation, the EQ settings may be sent only occasionally or periodically)may be sent from the subsystems 108 to the subsystem 110. In block 512,the subsystem 110 may coherently combine the signals from the pluralityof subsystems 108 ₁. In block 514, the subsystem 110 may decode, errorcorrect, and/or perform other processing of the combined signal torecover data (e.g., television content) carried in the signal. Thesubsystem 110 may comprise circuitry operable to decode and errorcorrect a plurality of channels concurrently for concurrently serving aplurality of client devices. In block 516 the recovered data may befurther processed for conveyance to client devices (e.g., televisions,set-top boxes, personal computers, and the like.).

FIG. 6 depicts example details of the subsystem 108 c of FIG. 1C. In theexample implementation depicted the subsystem 108 c comprises an analogfront end (e.g., corresponding to components 102, 104, 106, 109, 111 ofFIG. 1C), the digital front-end 112, and a partial demodulator 162. Thepartial demodulator 162 comprises a synchronization/timing recoverycircuit 604, an equalization circuit 606, a de-mapper 608 that isoperable to generate a soft decision output (e.g., LLRs) and a harddecision output, and a multiplexer 612. The multiplexer 612 may becontrolled by a control signal 611 based, for example, on receivedsignal strength, signal-to-noise ratio of a received signal, and/or anyother suitable characteristics of the received signal. For example,where an instance of the subsystem 108 receives a strong signal and/orhigh SNR signal, that instance of subsystem 108 may output LLRs to thesubsystem 110, but where the instance of subsystem 108 does not receivea strong and/or high SNR signal it may output nothing, and/or only harddecisions from the de-mapper to the subsystem 110. In this manner, morebandwidth on the LAN that connects the subsystems 108 to the subsystem110 may be allocated to instances of the subsystem 108 that have thebest reception, thereby resulting in a combined signal at the subsystem110 that is stronger and/or higher SNR.

In an example implementation, data sent over the link between subsystem108 and subsystem 110 may be compressed to further reduce the amount ofbandwidth needed on the link. Such bandwidth reduction may, for example,increase the number of subsystems 108 that a single subsystem 110 canconcurrently pair with. For example, where LLRs are sent over the link,entropy coding may be used to take advantage of the non-uniformdistribution of the LLRs.

FIG. 7 is a flowchart illustrating an example process for reception viaa distributed receiver. The example process begins with block 702 inwhich a signal is received by a subsystem 108. In block 704, thesubsystem 108 determines one or more characteristics (e.g., receivedsignal strength, SNR, or the like) of the received signal. In block 706the subsystem 108 determines whether the characteristic(s) is/are abovea determined threshold (“threshold1”). If the characteristic(s) is/arenot above threshold1, then, in block 708 the subsystem 108 does notoutput a signal to the subsystem 110. If the characteristic(s) is/areabove threshold1, then the process advances to block 710. In block 710the subsystem determines whether the characteristic(s) is/are above adetermined threshold (“threshold2”). If the characteristic(s) is/are notabove threshold2, then, in block 712 the subsystem 108 outputs a harddecision to the subsystem 110. If the characteristic(s) is/are abovethreshold2, then, in block 712 the subsystem 108 outputs a soft decision(e.g., LLR) to the subsystem 110. In this manner, since sending softdecisions may require more bandwidth, more bandwidth may be availablefor subsystems 108 which have “good” reception (e.g., high SNR) of thesignal.

The process of FIG. 7 may be implemented by each of a plurality ofinstances of the subsystem 108 (e.g., each of the instances in any ofFIGS. 3A-3F). Through a process such as the one depicted in FIG. 7,selective use of one or more of subsystems 108 may enable a receivercomprising a plurality of subsystems 108 and a subsystem 110 to receivesignals of a variety of standards, on a wide range of frequencies, andfrom a wide range of signal sources. That is, different subsystems 108can be used to receive different signals, from different sources, etc.

In various example implementations, a first semiconductor die (e.g., 210a) may comprise an interface circuit (e.g., 202) and a demodulationcircuit (e.g., 204). The interface circuit may be operable to receive anexternally generated (i.e. generated “off-chip” by, for example, anothersemiconductor die) signal and recover decisions of a symbol de-mappercarried in the externally-generated signal. The demodulation circuit maybe operable to recover one or more datastreams based on the decisions ofthe symbol de-mapper. The first semiconductor die may comprise circuitry(e.g., 202) operable to combine a plurality of signals from a pluralityof second semiconductor dice (e.g., 108 c), where each of the pluralityof signals comprises decisions of a respective one of a plurality ofsymbol de-mappers. The first semiconductor die may reside in a directbroadcast satellite (DBS) indoor unit (e.g., 314 or 302). Each of theplurality of second semiconductor dice may reside in a respective one ofa plurality of direct broadcast satellite (DBS) reception assemblies.The first semiconductor die may reside in cable television customerpremise equipment (e.g., 406). The demodulation circuit may be operableto perform forward error correction decoding based on the recovereddecisions from the symbol de-mapper. The interface circuit may beoperable to recover equalizer settings carried in theexternally-generated signal. The decisions of the symbol de-mapper maybe formatted as log-likelihood ratios. The decisions of the symbolde-mapper may be hard decisions when a corresponding signal-to-noiseratio is below a determined threshold and may be soft decisions whensaid corresponding signal-to-noise ratio is above said determinedthreshold.

Other embodiments of the invention may provide a non-transitory computerreadable medium and/or storage medium, and/or a non-transitory machinereadable medium and/or storage medium, having stored thereon, a machinecode and/or a computer program having at least one code sectionexecutable by a machine and/or a computer, thereby causing the machineand/or computer to perform the steps as described herein for adistributed receiver.

Accordingly, the present invention may be realized in hardware,software, or a combination of hardware and software. The presentinvention may be realized in a centralized fashion in at least onecomputing system, or in a distributed fashion where different elementsare spread across several interconnected computing systems. Any kind ofcomputing system or other apparatus adapted for carrying out the methodsdescribed herein is suited. A typical combination of hardware andsoftware may be a general-purpose computing system with a program orother code that, when being loaded and executed, controls the computingsystem such that it carries out the methods described herein. Anothertypical implementation may comprise an application specific integratedcircuit or chip.

The present invention may also be embedded in a computer programproduct, which comprises all the features enabling the implementation ofthe methods described herein, and which when loaded in a computer systemis able to carry out these methods. Computer program in the presentcontext means any expression, in any language, code or notation, of aset of instructions intended to cause a system having an informationprocessing capability to perform a particular function either directlyor after either or both of the following: a) conversion to anotherlanguage, code or notation; b) reproduction in a different materialform.

While the present invention has been described with reference to certainembodiments, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted withoutdeparting from the scope of the present invention. In addition, manymodifications may be made to adapt a particular situation or material tothe teachings of the present invention without departing from its scope.Therefore, it is intended that the present invention not be limited tothe particular embodiment disclosed, but that the present invention willinclude all embodiments falling within the scope of the appended claims.

What is claimed is:
 1. A system comprising: a first semiconductor diecomprising an interface receiver circuit and a demodulation circuit,wherein: said interface receiver circuit is operable to: receive anexternally-generated signal that carries decision outputs of a symbolde-mapper that is external to said first semiconductor die, saidexternally-generated signal comprising a plurality of time stamps, eachone of said plurality of time stamps corresponding to one of saiddecision outputs of said symbol de-mapper; and process theexternally-generated signal to recover said decision outputs of saidsymbol de-mapper carried in said externally-generated signal; and saiddemodulation circuit is operable to recover one or more datastreamsbased on said decision outputs of said symbol de-mapper.
 2. The systemof claim 1, said first semiconductor die comprising circuitry operableto combine a plurality of signals from a plurality of secondsemiconductor die, each of said plurality of signals comprising decisionoutputs of a respective one of a plurality of symbol de-mappers that areexternal to the first semiconductor die.
 3. The system of claim 2,wherein: said first semiconductor die resides in a direct broadcastsatellite (DBS) indoor unit; and each of said plurality of secondsemiconductor dice resides in a respective one of a plurality of directbroadcast satellite (DBS) reception assemblies.
 4. The system of claim2, wherein said first semiconductor die resides in cable televisioncustomer premise equipment.
 5. The system of claim 3, wherein: saidfirst semiconductor die resides in a baseband unit of a cellularbasestation; and each of said plurality of second semiconductor diceresides in a respective one of a plurality remote radio units of asatellite basestation.
 6. The system of claim 1, wherein said interfacereceiver circuit is operable to recover equalizer settings carried insaid externally generated signal.
 7. The system of claim 1, wherein saiddecision outputs of said symbol de-mapper are formatted aslog-likelihood ratios.
 8. The system of claim 1, wherein said decisionoutputs of said symbol de-mapper are hard decision outputs when acorresponding signal-to-noise ratio is below a determined threshold andare soft decision outputs when said corresponding signal-to-noise ratiois above said determined threshold.
 9. A method comprising: in a firstsemiconductor die comprising an interface receiver circuit and ademodulation circuit: recovering, via said interface receiver circuit,decision outputs of a symbol de-mapper carried in an externallygenerated signal, wherein said symbol de-mapper is external to saidfirst integrated circuit, said externally generated signal comprising aplurality of time stamps, each one of said plurality of time stampscorresponding to one of said decision outputs of said symbol de-mapper;and recovering, via said demodulation circuit, one or more datastreamsbased on said decision outputs of said symbol de-mapper.
 10. The methodof claim 9, comprising combining, via circuitry of said firstsemiconductor die, a plurality of signals from a plurality of secondsemiconductor die, each of said plurality of signals comprising decisionoutputs of a respective one of a plurality of symbol de-mappers that areexternal to the first semiconductor die.
 11. The method of claim 10,wherein: said first semiconductor die resides in a direct broadcastsatellite (DBS) indoor unit; and each of said plurality of secondsemiconductor dice resides in a respective one of a plurality of directbroadcast satellite (DBS) reception assemblies.
 12. The method of claim10, wherein said first semiconductor die resides in cable televisioncustomer premise equipment.
 13. The method of claim 9, wherein saidfirst semiconductor die resides in a baseband unit of a cellularbasestation; and each of said plurality of second semiconductor diceresides in a respective one of a plurality remote radio units of asatellite basestation.
 14. The method of claim 9, comprising recovering,via said interface receiver circuit, equalizer settings carried in saidexternally generated signal.
 15. The method of claim 9, wherein saiddecision outputs of said symbol de-mapper are formatted aslog-likelihood ratios.
 16. The method of claim 9, wherein said decisionoutputs of said symbol de-mapper are hard decision outputs when acorresponding signal-to-noise ratio is below a determined threshold andare soft decision outputs when said corresponding signal-to-noise ratiois above said determined threshold.